Sound-box for talking-machines.



H. W. HESS.

SOUND BOX FOR TALKING MACHINES.

APPLICATION FILED AUG. 7, 1913.

1,1 18,8- %50 Patented Nov. 24, 1914.

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SOUND BOX FOR TALKING MACHINES.

APPLICATION FILED AUG. 7, 1913.

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Specification of Letters Patent. P t t d 24., 1 1;,

Application filed August 7, 1913. Serial No. 783,514.

To all whom it may concern Be it known that I, HARRY W. Hess, a citizen of the United States, residing at New York, in'the county of New York and State of New York, have invented certain new and useful Improvements in Sound-Boxes for Talking-Machines; and I do hereby oleclare the following to bee full, clear, and eXact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same. 7 The present invention relates to a form of reproducer for talking machines by the use of which the tone arm and horn hitherto usedmay be dispensed with, while at the same time greater accuracy of reproduction is attained.

One object of the invention is the provision of an improved diaphragm having a peculiar conformation permitting a single disk to accommodate itself to sounds of all qualities within any reasonable degree of pitch, without imposing upon the particular changing forms of vibration imparted to it any material coercion due to its own natural tone.

Another object of the invention is the provision of means whereby one or more thinbined apparatus as employed with a disk record seen in edge view, Fig. 2 is an enlarged sectional view of thesame on the line 2-2 in Fig. 1, Fig. 3 is an enlarged sectional View of the mountingfor the needle arm looking-at right angles to Fig. 2, Fig. l is a face View of my preferred inrproved diaphragm, one quadrant only being shown. completed, and Fig. 5 is a sectional view of a small portionof thediaphragm.

Some of the novel features of my mounting shown in Figs. 1 to 3 will be found useful with diaphragmsof various forms, and Ido notlimit myself-to the employment of such features with .the peculiar improved diaphragm herein claimed.

Figure 1 is a front elevation of my com The disk record is indicated in the drawings at 10, and I mount a supporting ring 11 1n any suitable manner with relation to such disk. The particular mounting, is not A material to this invention and is not illustrated. Fitting within the ring 11 is the diaphragm 12, which I have shown indented, and on each side of the diaphragm is placed a parallel resonating to'ne plate 13, i l, separatedfromthe main diaphragm by suitable gasket rings l5, l6.- The collars 17 and 18 are fastened onto the ring 11, on the two sides to hold. the group of vibrant disks together. 7

The tone plates are accurately matched to the formation of the main diaphragm, as shown, and there is thereby formed a thin layer of air on each sideof the main diaphragm conforming to it in shape. It is to be understood that the gaskets 15 and 16 are made very thin, and the spacing of the various parts is exaggerated in 'the drawings for greater clearness.

- The needle arm is composed of two branches meeting at 19, and slightly tapering to permit closing down of the same upon a removable needle 20, by means of ascrew chuck 21. This simple construction permits of easy replacement of the needles,"but, at the same time, when in place, these latter are so firmly united to the arm, as virtually to form one piece with it. By this means the i minutest vibrations are transmitted without dlstortion. I The needle armis made up oftwosimilar separable branches of delicate spring structure, shown at 22 and 23, and each provided with a rounded enlargement 24, 25 bearing upon opposite faces of the main'diaphragm at or very. near its center. The arms 22, 23

pass through appropriate central'apertures in the tone plates 13 and 14. The degree of pressure exerted'by the" spring arms v22, 23, is regulated bya setscrew 26; and, of course, these pressures are equal, and therefore leave the main diaphragm quite free from any initial stress.

The arm and needle are supported upon the ring 11, by means of a leaf spring 27, gripped between the two parts of the needle arm, and is held by a fine set pin as shown in dotted lines, through which spring the V shank of the screw'26 passes quite loosely. ()ne end of this spring is thus fixed to the needle arm, while the other end terminates in a ball 28 fitting a socket in the ring 11,

as clearly shown in Figs. 2 and 3. The ball 28 is held up in place by a light strap or spring plate29 fastened at its ends to the ring 11, and provided with an opening embracing the outward curve of the ball 28.

In order to prevent useless movements and to confine the vibrations of the needle and arm to a plane substantially at right angles to the diaphragm, the ball is flattened on two sides as shown in Fig. 3. Other mountings permitting the vibratory movements described are within the scope of my broader claims.

In carrying out the construction so far described, I prefer to so proportion the parts that the center of gravity of the arm, chuck and needle lie as near as possible to the center of movement and in the plane of the diaphragm. It is also important for the best results'that the arm be balanced with respect to a plane passing through the center of motion and at right angles to the plane of vibration. For this purpose the screw 26 is constructed, substantially as shown in the drawing.

The construction thus far described may be employed with various forms of diaphragm, .but I prefer to use the diaphragm more completely illustrated in Figs. 4 and 5, which constitutes an important feature of the present invention.

In Fig. 4: a face view is afiorded of a quadrant of my improved diaphragm, and

it is to be understood that the remainder of the diaphragm is made like the quadrant fully illustrated. The dotted lines show the directions of successive rows of indentations. The gist of this feature of the invention lies in so forming the diaphragm that the active portions thereof, which. are free to respond to the vibrations imparted,

- are restricted in accordance with certain principles of construction which I have found highly productive of sensitiveness to all kinds of Waves. For this purpose the portions of the diaphragm which are not intended tobe responsive are stiffened by means 'of indentations 30, producing concavities on one side and correspondlng convexities on the other side. Broadly speaking this feature of my invention lies in applying to a diaphragm, rows of circular or polygonal indentations extending inward toward the center of the disk, these inden-v tations increasing in sizeoutward from the center as shown. Preferably this progressive increase in size is such as to causethe sum total of the diameters bf the indentations in any circle drawn around the center to represent a substantially uniform percentage of the total periphery of each circle. The depths of successive indentations in the various rows decrease' toward the center, preferably in the same proportion as the corresponding diameters of said indenta tions. Obviously, as the center is approached, observance of the above laws of construction will involve very delicate and accurate manipulation, and in practice there will be a certain area around the true center which will remain free of indentations. The smaller this area in proportion to the total area of the diaphragm, the more eX- cellent will be the results obtained. In the drawing no attempt has been made to show the exact structure very near the center, but

enough is shown to make clear the principles involved.

In the preferred embodiment of my invention, the rows of indentations follow a logarithmic spiral, which arrangement I have found to give the best results, and it will be observed that the indentations are so spaced that two sets of crossed spirals are produced, each affording reverse curves from one side of the diaphragm to the other. By

this means the vibrations traveling outward from the 'cener of impact are able to select natural outward and return paths of infinite varieties, according to their individual natures. Of course, the annular spaces covered by the clampingmeans are left flat.

It is obvious that the features which I have described andishown herein may be duplicated without departing from the invention, and indeed, many changes will occur' to those skilled in the art which can be made within the scope of this invention, and

I do not limit myself to the details herein shown and described.-

hat I claim is',

l-. A diaphragm for acoustic purposes furnished with rows of indentations extending inward toward the center, the succeeding .III 0 said indentations'being so proportioned and located that each row of indentations and the plane strip next to it are slightly convergent, and each narrows gradually inward, substantially as described.

it. A diaphragm for acoustic purposes furnished with rows of indentations each conforming to a reverselycurved line across the diaphragm.

5. A diaphragm for acoustic purposes furnished with rows of indentations each row conforming substantially to a reverse logarithmic splral across the diaphragm.

6. A diaphragm for acoustic purposes furnished with rows of indentations, eachrow conforming to a reversely curved line across the diaphragm, said indentations decreasing in depth and diameter toward; the center.

8. A diaphragm for acoustic purposes furnishedwith rows of indentations, each row conforming substantially to a reverse logarithmic spiral across the diaphragm, said indentations decreasing indepthanddiamv eter toward the center.

9. In a talking machine-reprdducer, a diaphragm, a needle bar having two resilient arms adapted to straddle. said diaphragm and a lating at will the mutual said arms.

10. In a talking machine reproducer, a needle bar comprising two thin spring contact. arms, means for clamping said arms upon a needle and means for adjusting the terminal pressures exerted by said arms toward each other. p v I 11. In a talking machine reproducer, a

pinge'thereon and means for regupressure, between diaphragm, a support therefor having a socket, a needle bar adapted to im i'nge against said diaphragm, a truncate ball fitting said socket and "connected with said bar and a strap fixed tosaid diaphragmsupport having an opening embracing a portion of said truncated ball and adapted to hold said truncated ball 1n place.

, 12 In a talking machine reproducer, a diaphragm, a support therefor having a socket, a needle bar adapted to impinge against said diaphragm, a truncated ball fitting said socket, means for holding said truncated ball in said socket and a flat spring connecting said needle bar and truncated ball. .1

13. A resonating cup for acoustic purposes, comprising m combination a diae phragm furnished with rows of indentations conforming to reversely curved lines across the diaphragm, and a resonating tone plate of identical conformation mounted parallel to said diaphragm and close to it.

a In testimony whereof I aifix' my signature, in presence of two witnesses.

Gm. A. BYRNE, C. JAMES 'Cno'nm. 

